Undercutting attachment for lathes



Oct. 5, 1954 M. F. RICE UNDERCUTTING ATTACHMENT FOR LATHES 5Sheets-Sheet. 1

Filed Jan. 5, 1954 Oct. 5, 1954 F. RICE UNDERCUTTING ATTACHMENT FORLATHES 3 Sheets-Sheet 2 Filed Jan. 5, 1954 Oct. 5, 1954 M. F. RICEUNDERCUTTING ATTACHMENT FOR LATHES 3 Sheets-Sheet 3 Filed Jan. 5, 1954 Le I1 a J j E M Ft Ft mt 3 Patented Oct. 5, 1954 UNDERCUTTING ATTACHMENTFOR LATHES Melvin F. Rice, Claremont, N. H., assignor to Cone AutomaticMachine Company, Inc., Windsor, Vt., a. corporation of VermontApplication January 5, 1954, Serial No. 402,328

3 Claims.

This invention relates to mechanisms for producing an undercut on workcarried by lathes and more particularly to an attachment for lathes forperforming this operation, and it has for an object to provide such anattachment which is operated entirely by motion of a tool carriage whichmoves substantially parallel to the axis of the rotary work-carryingspindle. Such an attachment is applicable to a multiple spindle lathe orscrew machine and is illustrated herein as applied to such a machine ofthe general type shown in the United States Letters Patent to Miller No.2,130,809 granted September 20, 1938, for Multiple Spindle AutomaticLathe.

Referring to the drawings,

Figure 1 is a fragmentary rear elevation of a multiple spindle latheembodying the invention.

Figure 2 is a detail sectional view to a larger scale on line 2-2 ofFigure 1.

Figure 3 is a fragmentary to plan view of the attachment and relatedparts, the undercutting tool being shown retracted.

Figure 4 is a view similar to Figure 3, but showing the tool in cuttingposition.

Figure 5 is a view similar to a portion of Figure 2, but to a largerscale.

Figure 6 is a detail sectional view to a larger scale on line 66 ofFigure 1.

Figure 7 is a view similar to a portion of Figure l but to a largerscale.

Figures 8 and 9 are detail sectional views on lines 88 and 3-43,respectively, of Figure 7.

Figures 10 and 11 are detail sectional views on lines llllc and H-l I,respectively, of Figure 9.

Referring first to Figures 1 and 2, there is illustrated a multiplespindle lathe having a lower bed i and an upper bed 2 spaced by endcolumns 3 and 5. An indexing drum 5 is mounted between the upper andlower beds l and 2 and within the column 4, this drum 5 carrying aplurality of rotary work carrying spindles 6 arranged in parallelcircular array about its central axis.

The drum is indexed by any suitable means well known in the art to bringthe several spindles successively into the same tooling station. Asshown there are eight spindles and the undercutting action is effectedat station #1, though it might be done at any other desired station.These stations are numbered, beginning at the bottom as shown in Figure2 and progressing clockwise, so that station I is in horizontalalinement with the central axis of the drum 5.

A tool carriage I0 is arranged for sliding motion on a central shaft IIwhich is coaxial with the drum 5. This carriage It is movable axiallytoward and from the drum 5, and as shown this is accomplished bysuitable cams (not shown) on a cam drum 15 mounted on a cam shaft Itjournaled in the upper bed 2 and in parallel relation to the indexingdrum 5 and the shaft ll. Thus as shown in Figure 1, the cams on the camdrum l5 act upon a follower [1 extending upwardly from a slide is fixedto the outer end of the carriage I0. This carriage Ill may be providedwith longitudinally extending T slots 20, as shown in Figure 2, for theattachment of suitable end Working tools which may operate at variousindex stations by reason of the axial motion of the carriage l3. At oneof these slots 20, there is secured the attachment by which theundercutting is effected in accordance with this invention. Theparticular slot employed, as shown herein, is the slot 260. opposite toindex station I. It is understood that various other cams may be carriedby the cam shaft l6 by which other operations and controls of themachine may be efiected, these, however, being immaterial to the subjectmatter of the present invention.

The attachment, as shown best in Figures 3 to H, comprises a blockhaving an inner face concaved to fit the outer face of the carriage l0and having suitable means by which it may be clamped to the carriage itas through bolts 26 having T headed nuts 2i thereon which engage in theslot 200.. The block 25, as shown best in Figure 6, has a pair of spacedoutwardly extending side walls 3d and 3! forming between them a guidewayfor a holder slide 32. Retaining strips 33 and 34 are secured, to thesewalls and Si and extend into opposed side grooves 35 of the slide 32.The retaining strip 33 also fixes adjustably to the block 25, a bar 35which is provided at the end nearest to the drum 5 with a cam face 37 asshown best in Figures 3 and 4. The bar 36 may have bearing thereonadjusting studs 38 by which the axial position of the bar 36 withreference to the block 25 may be adjustably fixed.

The slide 32 is provided at one end with a way 40 (see Figure 9)inclined to the length of the slide 32 so as to have a componenttransverse to the axis of the work carrying spindle at station I and acomponent lengthwise of this axis. This way 40 receives a lug 4|extending inwardly from a second holder or slide 42 which is mounted tomove lengthwise of the way 40 and is held in position by retainingstrips 43 and 44. This holder 42 may carry an undercutting tool securedthereto as by a stud 5| threaded into the holder 42, and the outer endof this holder 42 carries a cam follower roll 53. A spring 54 seated inthe way lfl bears between the closed outer end of the way and the lug 4|and normally presses the holder 42 with its follower roll 53 against oneend portion of a lever 55. This lever 56 has a looped portion as shownin Figure 11 against which the follower roll 53 bears, and it is securedto a pivot pin 5's extending through a bearing 58 formed in an extensionfrom the holder 32. This lever 56 has an arm 59 provided with a camfollower 69 which may bear against the cam face 37 of the bar 36.

The holder 32 may move relative to the block 25, but is normally held tomove therewith by a pair of springs 65 (see Figure 9) each engaging astop 65 secured to the holder 32 and reacting between the stop 63 and anabutment 67 adjustable axially by the adjustment of a screw 68. Each ofthese springs 65 is housed within a longitudinal passage as in the blockas shown best in Figure 6.

The holder 32 has fixed to its outer end a bar "iii which extendsoutwardly and slidably receives therethrough a stop rod ll having a pairof check nuts '52 threaded on its inner end. his stop rod "H is fixed toa stationary wall of the machine as at the column 3 as shown in Figure1.

In operation, as the carriage it is moved toward the work piece itcarries with it the block 25 and the holder 32 until such time as thenotion of the holder 32 is stopped by reason of engagem nt of the checknuts on the bar Further inward motion of the carriage Iii after thestopping of the motion of the holder 32 there ith acts to project thecam face 37 into nt with the lever 56 at the cam follower 6G, and rocksthis lever in a direction to move the tool-carrying holder 52 inwardlyand bacl wardly, bringing the tool 59 against the inner face of the workpiece 75 from the position shown in Figure 3 to that shown in Figure 4,so that the tool produces the desired undercut in the work piece.

On retraction of the carriage i t thereafter, the spring 5% acts towithdraw the tool from contact with the wori; piece to its osition ofFigure 3, whereupon further retraction of the carriage permits thesprings 65 to return the holder 32 to its normal relation to the camface 3? shown in Figure 3, whereupon further retracting motion of thecarriage it} removes the tool from the work piece axially to theposition shown in Figure 1 so that the spindles may be indexed to bringa succeeding work piece into station I, while that containing theundercut work piece is moved to the succeeding station 8.

From the foregoing description of an embodiment of this invention itshould be evident to those skilled in the art that various changes andmodifications may be made therein without departing from its spirit orscope.

I claim:

1. In combination with a lathe having a rotary work carrying spindle anda tool carriage movable substantially lengthwise of said spindle, of amain holder carried by said carriage and movable relative theretosubstantially axially of said spindle, a second holder mounted on saidfirst holder for motion relative thereto in a direction havingcomponents parallel and transverse to the axis of said spindle, a leverpivoted to said main holder and having a portion engageable with saidsecond holder to move said second holder as said lever is swung, meansfor stopping the motion of said first holder with said tool carriage ata predetermined point, a cam fixed to said tool carriage and engageablewith said lever for moving said lever by continued motion of saidcarriage after motion of said holder with said carriage has beenstopped, and a tool carried by said second holder for operating on workheld by said spindle during the continued motion of said tool.

2. An undercutting attachment for a lathe having a rotary work carryingspindle and a carriage movable substantially lengthwise of said spindle,which attachment comprises a main holder carried by said carriage andmounted for sliding motion relative to said carriage substantiallylengthwise of said spindle, a second holder movably carried by saidholder in directions having a component transverse to said axis and acor ponent lengthwise of said axis, a tool carried by said secondholder, a cam fixed to said tool carriage, means limiting the motion ofsaid main holder with said tool carriage at a predetermined position ofsaid tool carriage, and operative connections to said second holderactuated by said cam on continued motion of said tool carriage af er themotion of said main holder has been stopped for moving said secondholder in a manner to cause said tool to undercut a work piece carriedby said spindle.

3. An undercutting attachment for a lathe having a rotary work carryingspindle and a carriage movable substantially lengthwise of said spindle,which attachment comprises a main holder carried by said carriage andmounted for sliding motion relative to said carriage substantiallylengthwise of said spindle, a second holder niovably carried by saidmain holder in directions having a component transverse to said axis anda component lengthwise of said axis, a tool carried by said secondholder, a cam fixed to said tool carriage, means limiting the motion ofsaid main holder with said tool carriage at a predetermined position ofsaid tool carriage, and operative connections to said second holderactuated by said cam on continued motion of said tool carriage after themotion of said inain holder has been stopped for moving said secondholder in a manner to cause said tool to undercut a work piece carriedby said spindle, said operative connections including a lever pivoted tosaid main holder having a follower engaged by said cam and operativelyengaging said second holder.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,647,368 Lovely Nov. 1, 1927 1,678,924 Strindberg July 1,1928 1,793,718 Price Feb. 24, 1931 1,794,396 Trobeck Mar. 3, 1931

